1. Field of the Invention
The present invention relates to a device for transferring heat energy from a refrigeration circuit to a hot water system. More particularly, the present invention concerns a combination refrigerant desuperheater hot water heater and a method of integrating same into an air conditioning system.
2. Description of the Prior Art
In a typical vapor compression refrigeration system various components such as a compressor, condenser, evaporator and an expansion device are arranged to transfer heat energy between fluid in heat exchange relation with the evaporator and fluid in heat exchange relation with the condenser. It is also known in conjunction with such refrigeration systems to utilize desuperheaters for removing superheat energy from the gaseous refrigerant prior to circulating said refrigerant to the condenser.
In a conventional building installation a hot water heater is provided to supply heated water to an enclosure. Many hot water heaters have a cold water inlet connected to an inlet extension pipe and a hot water outlet extending through the top of the hot water tank. It is known to make the appropriate water connections between a hot water heater and a refrigeration circuit desuperheater such that water is conducted from the water supply system to the refrigerant desuperheater where it is preheated prior to being conducted back to the hot water tank. In air conditioning systems when cooling is required, heat energy is transferred from the enclosure and discharged to the ambient or some other heat sink. This heat energy is often wasted. With the combination system as disclosed herein it can be seen that this heat energy that is unwanted in the enclosure may be utilized to supply heat energy to water to provide heated water for various end uses. This heated water may be used for bathing, cleaning, cooking or other uses in a residence. Commercial applications include restaurants, supermarkets, process utilization and any other application wherein waste energy or excess energy from a refrigeration system may be utilized to provide some or all of the hot water heating needs.
In addition to refrigeration systems providing excess heat for heating water during the cooling system, certain refrigeration circuits are capable of reversing the cycle of operation for providing heat energy to the enclosure during the heating season. This type of refrigeration circuit is commonly referred to as a heat pump. If it is desirable, some of the heat energy provided during the heating season with the heat pump may also be utilized to supply hot water through the disclosed hot water heater refrigerant desuperheater.
In the specific embodiment disclosed an air conditioning system commonly known as a triple split system, is utilized to provide a combination operation. A triple split system as utilized herein will include a refrigeration circuit having three separate sections, an outdoor section including an outdoor heat exchanger mounted in heat exchange relation with the ambient air, an indoor section mounted in heat exchange relation with the heat transfer fluid being circulated throughout the enclosure for effecting heating or cooling, and a compressor section including the compressor of the refrigeration circuit and the combination refrigerant desuperheater hot water heater.
The control of the water flow through the combination desuperheater hot water heater is specifically arranged to allow for efficient and safe operation of the system. As disclosed, a pump is operated continuously when the compressor of the refrigeration circuit is operated such that water is continually circulated from the water connecting system to the heat exchanger. A bypass line is located in a parallel flow path with the combination desuperheater hot water heater. The bypass line includes a restricted orifice for limiting the volume of water flow through the bypass line. An entering water temperature sensing device is located to sense the temperature of the water entering the unit. A leaving water temperature sensing device is located to sense the temperature of the water leaving the combination desuperheater hot water preheater. A valve is located to control the flow of water through the combination desuperheater hot water heater and a safety sensor is located to determine the temperature of the water being discharged back to the hot water heating system. The pump operating in conjunction with the compressor acts to circulate water through the combination desuperheater hot water preheater when the incoming water temperature is below the desired water temperature and when the leaving water temperature is above the temperature to which it is desired to heat the water.
The safety sensor serves to de-energize the complete control circuit including the compressor of the refrigeration circuit to prevent water flow from the combination desuperheater hot water heater should the water temperature rise above a safe level for delivery of water within the residence. All of the temperature sensors are connected in series to the water valve to form an integrated control arrangement for regulating the flow of water through the combination desuperheater preheater. The utilization of the restricted flow bypass allows for a continual amount of water circulation such that accurate temperature readings may be maintained.
The addition of the safety temperature sensor for controlling the water valve in the system allows potential hot water overheating problems to be avoided should either of the primary control components fail. In a residence it is possible to open a hot water tap and to get a short blast of extremely hot water directly from the preheater. By providing this safety device water above an excessive temperature is not allowed to enter the water tank or the return line to the hot water heating system and hence potential problems are avoided.